Dorso-ventral (DV) patterning in the Drosphila embryo depends on a cascade of maternal genes that define ventral activation of the Toll receptor. Ventrally restricted Toll signaling leads to the formation of a ventral to dorsal nuclear gradient of Dorsal, member of the NFkappaB family of transcription factors, and formation of the mesodermal and dorsal ectodermal domains of the embryo. We have discovered a maternal function of decapentaplegic (dpp) and short gastrulation (sog) genes that impacts on the formation of the Dorsal gradient. sog and dpp function antagonistically to influence translocation of Dorsal into the nucleus. Epistasis experiments have allowed us to place the effect of Dpp signaling downstream or in parallel to the Toll receptor, indicating cross-regulation between the TGF-beta and IL-1 signal transduction pathways. Our goal is to investigate the mechanism by which maternal Toll and Dpp pathways interact to pattern the DV axis of the embryo. Considering that elements of TGF-beta and IL-1 signaling are conserved among vertebrates and invertebrates, by uncovering these mechanisms we might gain insights towards general cross-regulatory interactions between these pathways.